Targeted Synthesis of Silicomolybdic Acid (Keggin Acid) inside Mesoporous Silica Hollow Spheres for Friedel-Crafts Alkylation

被引:129
作者
Dou, Jian [1 ]
Zeng, Hua Chun [1 ,2 ]
机构
[1] Natl Univ Singapore, Fac Engn, Dept Chem & Biomol Engn, Singapore 119260, Singapore
[2] Inst Mat Res & Engn, Singapore 117602, Singapore
关键词
MOLYBDENUM OXIDE CATALYSTS; HETEROPOLY ACIDS; SHELL STRUCTURE; SPECTROSCOPIC CHARACTERIZATION; TIO2; NANOSPHERES; MOLECULAR-SIEVES; PORE STRUCTURE; SURFACE; RAMAN; NANOCRYSTALS;
D O I
10.1021/ja3055723
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Herein we report an inside-out preinstallation-infusion-hydration method for targeted synthesis of Keggin heteropoly acids (silicomolybdic acid, H4SiMo12O40) within mesoporous silica (SiO2) hollow spheres. In this process, discrete molybdenum dioxide (MoO2) nanoparticles with diameter size ranging from 25 to 60 nm were first prepared by a one-pot hydrothermal route in water/ethanol mixed solvents at 180 degrees C, which were then used as cores to grow the shell of supramolecular templated silica with tetraethyl orthosilicate (TEOS) and hexadecyltrimethyl- ammonium chloride (CTACl) in alkaline solution. By thermal treatment of as-synthesized MoO2@SiO2 core-shell spheres, the organic template was burned off and mesoporous shell was formed (BET specific surface area was as high as 872 m(2)/g). Meanwhile, the encapsulated MoO2 was oxidized to Mo6+ and infused to the mesoporous silica shells, forming heptamolybdate species (Mo7O246-) uniformly dispersed on the mesopore surfaces of silica, while generating void space at the center of spheres. After hydration with water, H4SiMo12O40 was formed by reaction between the surface Mo7O246- and silica species in the presence of water. The prepared H4SiMo12O40@mSiO(2) hollow spheres were tested for Friede-Crafts alkylation of toluene by benzyl alcohol. The H4SiMo12O40@mSiO(2) catalysts fabricated via this novel route exhibited excellent catalytic activity toward benzylation of toluene, which was approximately 2.6 times as high as that of commercial Amberlyst-15 catalyst. In addition, the H4SiMo12O40@mSiO(2) catalyst was very robust and could be reused after regeneration.
引用
收藏
页码:16235 / 16246
页数:12
相关论文
共 82 条
  • [31] Hierarchical order in hollow spheres of mesoporous silicates
    Lin, HP
    Cheng, YR
    Mou, CY
    [J]. CHEMISTRY OF MATERIALS, 1998, 10 (12) : 3772 - +
  • [32] ZSM-5 Zeolite Single Crystals with b-Axis-Aligned Mesoporous Channels as an Efficient Catalyst for Conversion of Bulky Organic Molecules
    Liu, Fujian
    Willhammar, Tom
    Wang, Liang
    Zhu, Longfeng
    Sun, Qi
    Meng, Xiangju
    Carrillo-Cabrera, Wilder
    Zou, Xiaodong
    Xiao, Feng-Shou
    [J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2012, 134 (10) : 4557 - 4560
  • [33] Toluene alkylation with 1-octene over supported heteropoly acids on MCM-41 catalysts
    Liu, Yu
    Xu, Lin
    Xu, Bingbing
    Li, Zhikui
    Jia, Liping
    Guo, Weihua
    [J]. JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL, 2009, 297 (02) : 86 - 92
  • [34] Transesterification of triacetin with methanol on Nafion® acid resins
    Lopez, Dora E.
    Goodwin, James G., Jr.
    Bruce, David A.
    [J]. JOURNAL OF CATALYSIS, 2007, 245 (02) : 381 - 391
  • [35] Alumination and ion exchange of mesoporous SBA-15 molecular sieves
    Luan, ZH
    Hartmann, M
    Zhao, DY
    Zhou, WZ
    Kevan, L
    [J]. CHEMISTRY OF MATERIALS, 1999, 11 (06) : 1621 - 1627
  • [36] Photocontrolled reversible release of guest molecules from coumarin-modified mesoporous silica
    Mal, NK
    Fujiwara, M
    Tanaka, Y
    [J]. NATURE, 2003, 421 (6921) : 350 - 353
  • [37] Access in mesoporous materials: Advantages of a uniform pore structure in the design of a heavy metal ion adsorbent for environmental remediation
    Mercier, L
    Pinnavaia, TJ
    [J]. ADVANCED MATERIALS, 1997, 9 (06) : 500 - &
  • [38] Möller K, 2007, ADV FUNCT MATER, V17, P605, DOI 10.1002/admf.200600578
  • [39] One-Step Synthesis of Hierarchical Zeolite Beta via Network Formation of Uniform Nanocrystals
    Moeller, Karin
    Yilmaz, Bilge
    Jacubinas, Richard M.
    Mueller, Ulrich
    Bein, Thomas
    [J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2011, 133 (14) : 5284 - 5295
  • [40] Inclusion chemistry in periodic mesoporous hosts
    Moller, K
    Bein, T
    [J]. CHEMISTRY OF MATERIALS, 1998, 10 (10) : 2950 - 2963